replacing the tundra 26 gallon tank with oe 38 gallon tank

i got sick of abusing the letter "e" on my fuel gauge and decided to step up from
the little 26 gallon tank. original plans were to get a transfer flow 46 gallon
tank, but when i found they were discontinued (but with a couple still in stock), i
did some soul searching and realized that was maybe a bit more fuel than i need 99%
of the time and i didn't want that much weight.
looking at the oe tank, it's about 60lbs lighter dry and even with an rci skid plate
is still about 40lbs lighter. pricewise they were about the same.

when the box showed up, i thought the tank was really well packaged in an enormous box...nope...the tank is just enormous. (note: the retaining ring on the new tank did not come with the tank..i had put it there so i didn't lose it. also, 26 gallon tank is not taller...it's sitting on a roller)

fortunately, someone had already done the mod on tundras.com so i robbed his parts list and went shopping. unfortunately, he did a limited write up and didn't deal with the parking brake issue, so here's my write up. these tanks are also discontinued, but when i ordered mine, there were 41 in the country. here's the list of parts

what you do need
-tank 77001-0c120
-crossmember 51038-0c040
-forward strap 77601-0c110
-pin for strap 77653-35020
-cotter pin for pin 90468-14032
-bolt for strap 90119-a0249
-gasket for the fuel module 77169-0C010
NOTE: if you plan on adding a o.e. "skid" plate or an rci, you will need different straps.

optional items are
-retainer for fuel module (they sometimes break, mine didn't so if you need one, hit
me up) 77144-08010
-heat shield one 77697-0C050
-heat shield 2 77697-0C060
-fuel tank skid 77606-0C040 (this may require mounting brackets, i'm not sure. i
am putting an rci skid on mine)
-the original poster on tundras.com said you needed the number 2 (forward on the 26
gln tank) strap, pn 77601-0C120, but it measured the same as the my old one (26" end
to end). the rearmost strap is the same.
-original poster also recommended changing out the fuel sender float on higher
mileage rigs. mine is low miles so again, i skipped...83320-0c060

tools needed
-14mm socket, short extension and ratchet
-2 vacuum caps to put over the fuel lines
-phillips head or 10mm socket, long extension and ratchet
-welder or drill with awesome bits and a lot of patience (unless you have a 2015 or newer, they are already drilled for the crossmember)
-grinder and cutoff wheels
-floor jack and stands
-patience and alcohol...lots of alcohol

have the tank as close to empty as possible. there's no drain like land cruisers and there's an anti-siphon measure in the tank. trying to get fuel out of it will suck and it will make the tank unstable when trying to get it out.

disconnect the battery. i was planning on welding and i still am a bit paranoid about frying electrical stuff by welding on the frame with the battery connected.

get it up in the air. mine is stock height and there was no way i could mess around with the crossmember sitting on the tires. i filled the air bags and had the front up on jack stands.

put a jack under the tank. there's a circle on the bottom..put it just to the inside of that so if the tank shifts, it leans against the frame.
undo the two strap bolts and pull the pins on the side at the center of the truck and set aside.

at the front of the tank, there are two fuel lines. take a photo before you undo them so you make sure to hook them up the same. undo the lines by pushing the locking clips up (they only go up a little bit) and pressing the two blue sides in while wiggling the lines off. the blue buttons you press are a pita...i used a couple screw drivers to press them in and loosen them initially, then one screwdriver and my finger while wiggling them off. they will spin making it a bit more difficult. (in the photo, the yellow clip is unlocked, the brown is still locked)

to get the vent hose and fuel filler, go right inside the fenderwell in front of the rear tire and look forward and up. the vent comes off the same way as the two hoses above. the filler neck has clamps.

last line is the evap line to the canister at the back top of the tank. the clip will pull back off the fitting until it almost comes out, then the hose will just wiggle off (no buttons to push)

drop the tank about halfway down. you may have a cheap plastic cover over the fuel module (you may not...i never saw any reference to it in the videos i watched, but i had one). pop that off, then unhook the electrical connector, finish dropping the tank and pull it out from underneath

now you need to remove the fuel module. there apparently is a tool, but most use a hammer and screwdriver. there are tabs that you will need to occasionally need to push in (think pill bottle). tap a couple times, then go 180 on the retainer and tap again. the retainer will actually shift and can become cocked which is why you need to work opposite sides. you will see the three "finger" tabs and they will hit the bumps on top of the module (3 fingers, 4 bumps). just push the finger in until you get past the bump.

keep working the retaining ring off this way. the fuel module is spring loaded and will pop up when you finish unscrewing the ring. DO NOT let the fuel module spin. when you get the ring off, you will see a small tab sticking out from the edge of the module. that sits in a gap and that is how you know the pump and fuel sender are located properly...i broke mine

slowly work the module out of the tank. it will have a good quart or so of fuel in it that will flow out as you remove the module.

begin by putting a thin layer of grease or oil on the new module seal (this helps keep the oring from twisting during installation). set the fuel module and seal into the new tank and install the retaining ring using the same side to side tapping motion with the hammer and screwdriver that you used to remove everything.

when it gets snug, keep going until the arrow on the retaining ring matches the arrow on the fuel tank. now it's time to move onto the evil portion...the crossmember

you can not install the crossmember without notching it. the o.p. just cut a large section out of each bottom. i went further and cut the bottom completely off. here's a photo robbed from someone else's install so you get the pic of the minimum amount of chopping needed

i'm not known for my patience and after multiple times of trying to get a w shaped crossmember under the driveshaft, over the exhaust and wedged into the frame, i hacked straight across and took the bottoms of the ears off.

the 2nd gens do not have the holes to bolt the crossmember in and i have slee sliders and didn't want to drill through the frame and the slider mounts, so i was going to weld it in anyways and didn't need the lower section. on a 2015 and up with the holes already drilled, i would've tried this cut.

at this point i was thinking i had to be close to done because the thread i read talked about how straightforward the install was. after questioning the op later, he forgot to mention a lot and 'doesn't use his parking brake'. this is pertinent because the hard fuel lines on the side of the frame and the park brake bellcrank are both right in the way of where the crossmember needs to sit.

i shimmed the fuel lines up about 3/4 of an inch and a combo of notching the crossmember and shimming the bellcrank mounts with a few washers took care of that issue. i kept trying to keep notching to a minimum, but i lack of patience took over and i finally notched the crap out of the top of the crossmember.

now i was ready to figure out exactly where the crossmember needed to be and weld it in place. to do that, i put the tank up into place and hooked up the front and rear straps (the middle strap originally appeared to be 2 1/2" too short, so i left it off for this part).

using a paint pen, i marked where i needed to clear for welding and marked the lip of the frame to show where the crossmember needed to sit and i pulled everything back out again to clean the frame for welding.

i was a little leery about this part because the two fuel lines are RIGHT THERE, but the vacuum caps kept the fumes at bay while i ground the paint off and welded the crossmember in place. i did have one issue there where one ear on the passenger side needed to be shimmed, as if it was bent or made to be installed a bit diagonally. once welded, i painted everything up and begain reinstallation of the tank.

put the floor jack on the round portion of the bottom of the new tank (no fuel to slosh around and throw it off balance now) and jack the tank almost all the way up so you can install the electrical connection. once clipped in, jack the tank the rest of the way up until you can get front and rear straps in place and holding the tank. i did not remove the floor jack yet. i was going to put the middle strap on with a longer bolt but wanted to make sure the tank was well in place.

i clipped the two front hoses back on by pushing them until i heard the audible click then pushing the locks down. from there, i got the filler neck off the old tank and installed it and hooked up the vent tube. the last tube, the evap tube, didn't appear to be long enough either but i pulled it out of it's resting spot (see the pic of the tanks in the first post and you can see how it rests in a groove).

with the lines all hooked up, i put a little bit of pressure on the tank with the floor jack and tightened the front and rear straps all the way. this revealed that the middle strap was long enough.

the first fill has been done and i have no fuel smells and the truck is running great. with 5 gallons, the needle of the gauge is on the "e" line. with 10, the light is out. the real test will be at the end of the month when i head to idaho.

Cool write up
I wish I had the larger tank on my 15.
I get tired of reading “4 miles to empty” too.

Click to expand...

Thanks.
Your 2015 should be a bit easier to add the tank as your frame should be drilled.
As for the "4 miles to empty?", mine is a grade model so until I mod the cluster/ wiring harness, I dont get that info. I have the switch, but can only switch between celcius and Fahrenheit

-Are you running Slee sliders? - (seem like we talked about them, but I also had my concussion between then & now )

If so, no issues fitting this fella up there with the Slee steel hanging off the framerails? Or if so, was it minor grinder clearance-type work?

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Also, hit me up if you want about that switch where we both had blanks - my trip computer all came alive with what was already prewired to that harness socket the switch plugs into.
I can take a pic of my plug/wires so we can compare - maybe you got a bum switch????
I’m even trying to figure out if I can make the sonar work since I am 60% sure I found the sensor plugs doing my Demello bumper, and prob just need to find where the sonar ECU should be, get one & install that w/ sensors to make it work.

I was surprised my tow mirrors had both the LED running & turn signals pre-wired, when my Rock Warrior is really just Bilsteins on a normal SR5.

i do have the slee sliders. no issues with the sliders unless you drill the frame for the crossmember (i welded it in). then you have to drill the frame and the slider mounts.

no bum switch. i have found that a lot of the grade model trucks are missing various wires and sections of harness (like i have the plug in the overhead and the plug under the truck for the camera, but i'm missing the section of harness behind the glove box).

someone else documented which slots in the plugs need to have wires and i don't have wires there. he cheated and splices wires on the backside and of the plug, then soldered them to the piece on the cluster that controls the read. i don't want to do that so i'm gonna hit up a local toyota guru to see if he can find me the pin parts so i can properly add the missing wires